Armature for dynamo-electric machines



UNITED STATES PATENT OFFICE.

GEORGE V. FULLER, OF NORlVICH, COXNFCT'TCUT.

ARMATURE FOR DYNAMO-ELECTRIC MACHINES.

SPECIFICATION forming part of Letters Patent No. 286,415, dated October 9, 1883.

(X model.)

To all whom it may concern:

3e it known that I, Gnonon XV. FULLER, of Norwich, Connecticut, have invented an Improvement in Armatures for Dynamo-Electric Machines, of which the following is a specification.

My invention relates to the class of armatures for dynamo-electric machines in which .cores of the armatnres are composed oiiron spirals, with the object of preventing the existence in the core of any closed circuit in which currents of electricity can be established b yindu ction. It is especially intended for the employment for the core of a cylindrical armature having induction-coils which traverse its exterior longitudinallyupon opposite sides.

My invention consists in forming the core of a comparatively thin iron plate in the form of a spiral, which is supported upon the armature-shaft, but preferably insulated therefrom and from the heads by which it is sccnred in position. By this construction the magnetic field is nearly filled with iron, and yet does not present a continuous circle or metal capable of constituting a closed eleetrical. circuit in which currents ol electricity can be. established by induction.

Instead of employing a single spiral, I may use two or more spirals of. like pitch and diameter, and arrange them in the core with their convolutions relatively interplaced.

A. result which approximates that attained by my improvement may be obtained by using for the core a cylinder of iron which not insulated from the armatureshatt, but which has a deep spiral. groove formed in its periphery. The inductive influence which tends to establish currents of electricity is most ener getically exerted upon the exterior portion of the core; hence the usefulness of the spiral grooving by which the existence of a closed or continuous electrical circuit in the exterior portioirol' the core is prevented.

Theaccompanying drawings, illustrating an armature-core embodying my invention, are

follows:

Figure 1 is an end view. Fig. 2 is a longitudinal section through the line w m on Fig. 1. Fig. 3 is an elevation showing several convolutions of the spiral detached from the shalt. Fig. 4 a partial longitudinal section through the line :0 a on Fig. 1, showing a modification of the spacing-strip for separating and insulating the convolntions of the spiral iron plate from each other.

The armature-shaft A is adapted for rotation in the machine in the usual manner. Its central portion is surrounded with the sleeve of insulating material 13, outside of which is the iron spiral C. Immediately adjoining the sleeve B is a spiral strip, D, of paper, rubber, or other insulating material, the convolutions of which are interplaced with the convolutioi'is of the spiral plate C, which is intended for employment for the purpose of holding apart or spacing the convolutions of the spiral C, especially when the latter is composed of very thin plates. The spacing-strip I) may be narrow, as shown in Fig. 2, so that the air spaces (1 are established between the convolutions of the plate 0; or the strip 1) maybe made of thin material.such as paperand may be of the same width as the plate 0, as shown in Fig. 4.

The spiral plate (1 is secured in position between the collar E, ailixed to one end of the shaft A and the nut F screwed upon the other end of the shaft, and prevented from being jarred loose by the conically-formedjam-nut /l The collar E is provided with a conical. hub, e, and. the nut F has the central portion of its inner face similarly formed, while. its exterior face is centrally recessed to receive the conical periphery of the jam-nntjl' flhelatter is pro vided with the holesff for the reception ofthe driver, by which it is screwed on or off the shaft A.

The nut F has four holes tapped through it to receive the steadyscrews G (i G (1, the inner portions of the shanks of which are re spectively received within the tubes g of in sulating material,which are inserted, respect ively, through. holes in two or more of the ad joining eonvolutions of the spiral plate The spiral C is centrally countersunk at each end to enable its end convolutions to clear the peripheries of the hub e and the conical projection of the nut F.

W'ashers H H of insulating material are introduced, respeetivcl y, between the ends of the ICO spiral G and the inner faces of the collar' and the nut F.

It is not deemed necessary to show all the parts of a dynamo-electric machine, nor to in- 2 aux 115 dicate the method of applying the inductioncoils to such an armature-core, inasmuch as the use of cylindrical armatures in such machines and the method of applying inductioncoils to them are common and well known.

By this mode of construction the spiral plate, which constitutes the core, and by which the magnetic field'is substantially filled with a mass of iron, is insulated from the shaft and the terminals of the spirals of which the core is composed are insulated from each other, so that the core does not present a continuous circle of metal capable of constituting a closed electrical circuit in which currents of electricity can be established by induction when the armature is employed in a dynamo-electric ma; chine. 1 e

I claim as my invention in a dynamoelectrio machine- 1. A cylindrical armature-core composed of an iron plate or piates formed spirally around the armatureshaft, in combination with induction-coils longitudinally traversing the core upon opposite sides thereof.

2. A cylindrical armature for a dynamoelectric machine having its core composed of a spiral or spirals, of iron plates insulated from the armature-shaft, and having the terminals of the spiral or spirals insulated from each other, for the purpose of substantially filling the magnetic field with iron, while preventing the existence in the core of a closed electrical circuit in which currents of electricity can be established by induction when the armature is employed in the usual manner in a dynamoelectric machine.

'3. In a cylindrical armature, substantially such as described, the spacing-strip D, interplaced with the convolutions ofthe spiral iron plate or plates of which the core is composed, as and for the purposes set forth.

GEO. W, FULLER.

Witnesses:

J OHN E. EAn E, Jos zrrr Q. EARL-YE. 

